OK damnit I'm tired of these bizarre frame rate issues. Yes I had a heating problem but I solved it. I run GPU-z perpetually now and never exceed 80c.

I'm coming to the conclusion that game has serious CPU issues. Think about it: how on Earth can Divinity 2 on Gamebryo be a bigger hit than Fallout 3 on Gamebryo? Divinity clearly has less detail in the landscape and far less detail in the models than FO3.
I'll see Fraps at 15 FPS occasionally looking at a rock. I ALT+TAB and there it is, CPU pegged while my GPU is lumbering on in the 70c range. I can get a few FPS back by dropping settings but even that is erratic.

Anyway, its still playable but when its chugging along with FPS in the upper teens I'll be damned if I see anything in front of me to justify it. Gothic 3 had better framerates!